Saturday, November 26, 2016

4.1 Miles

A coast guard captain on a small Greek island is suddenly charged with saving thousands of refugees from drowning at sea.

From New York Times  by Daphne Matziaraki

When I returned home to Greece last fall to make a film about the refugee crisis, I discovered a situation I had never imagined possible.
The turquoise sea that surrounds the beautiful Greek island of Lesbos, just 4.1 miles from the Turkish coast, is these days a deadly gantlet, choked with terrified adults and small children on flimsy, dangerous boats.
I had never seen people escaping war before, and neither had the island’s residents.
I couldn’t believe there was no support for these families to safely escape whatever conflict had caused them to flee.
The scene was haunting.

Regardless of the hardship Greeks have endured from the financial crisis, for a long time my home country has by and large been a peaceful, safe and easy place to live.
But now Greece is facing a new crisis, one that threatens to undo years of stability, as we struggle to absorb the thousands of desperate migrants who pour across our borders every day.
A peak of nearly 5,000 entered Greece each day last year, mainly fleeing conflicts in the Middle East.

 Lesbos island (NGA chart in the GeoGarage platform)

The Greek Coast Guard, especially when I was there, has been completely unprepared to deal with the constant flow of rescues necessary to save refugees from drowning as they attempt to cross to Europe from Turkey.
When I was there filming, Lesbos had about 40 local coast guard officers, who before the refugee crisis generally spent their time conducting routine border patrols.
Most didn’t have CPR training.
Their vessels didn’t have thermal cameras or any equipment necessary for tremendous emergencies.
Suddenly, the crew was charged with keeping the small bit of water they patrolled from becoming a mass grave.

Each day, thousands of refugees crossed the water on tiny, dangerous inflatable rafts.
Most of the passengers, sometimes including whoever was operating the boat, had never seen the sea.
Often a motor would stall and passengers would be stranded for hours, floating tenuously on a cold, volatile sea.
Or the bottom of a dinghy would simply tear away and all the passengers would be cast into the water.
The coast guard felt completely abandoned, they told me, as if the world had left them to handle a huge humanitarian crisis — or allow thousands to drown offshore.
I followed a coast guard captain for three weeks as he pulled family after family, child after child, from the ocean and saved their lives.
All the ones in this film were shot on a single day, October 28, 2015.
Two additional rescues happened that same day but were not included.

The problem is far from over.
Many of the refugees come from Syria, where Russia is intensifying bombings that are killing thousands of civilians and devastating Syrian cities.
The United States is planning to respond.
According to the Greek Coast Guard, thousands of families with children are lining up along Turkish shores to make the unsafe crossing to Greece.

In making this film, I was struck by the fine lines that separate us, the moments when our paths cross fleetingly, and we look at one another for the first time and sometimes for the last.
This film shows that crucial moment between life and death, where regardless of political beliefs, fears or preparation, some people will go beyond themselves to save a stranger.

And it raises questions about our collective responsibility — the choices we all make for ourselves, and for others.
We don’t all confront the refugee crisis with the same immediacy as the coast guard captain portrayed here.
But as our world becomes more interconnected, and more violent, we do all face a choice — would we act as he does, to save the life of stranger?
Or would we turn away?

Links :

Friday, November 25, 2016

The grounding and sinking of MV 'Minna'

Resolution island with the GeoGarage platform (NGA chart)

From Hydro by David H. Gray


The high cost of exploration in subarctic, often uncharted, waters was demonstrated in an unorthodox but convincing way by the 1974 grounding and sinking of the MV Minna off Resolution Island [Canada] while conducting a combined hydrographic-geophysical survey in the northern Labrador Sea.

Minna aground at the left of photo, and the large panel radar arrays on the mountain top — in Resolution Island (Nunavut).
photo : John Newton

Minna was an 83.6m long (274ft), ice-strengthened freighter built in 1960 at Arendel, Norway, as MV Varla Dan and subsequently sold to the Karlsen Shipping Company of Halifax who changed her name.
Bedford Institute of Oceanography (BIO) in Dartmouth, Nova Scotia, Canada, chartered her in 1972, 1973, and 1974 for deep-sea hydrographic and geophysical surveys in the Labrador Sea.
Given that she was only carrying survey equipment, 300 tons of concrete ballast, and was light on fuel, her displacement at the time of the grounding would have been about 3000 tons.

Austron 5000 LORAN-C receiver (with visor over the oscilloscope), PDP-8 computer, and paper tape reader.
In the right-hand rack, third and fourth pieces from the top

The Survey Equipment

Navigation for hydrographic and geophysical surveys on the Minna was obtained from:
  1. Two range DECCA-LAMBDA 12-f, with Master transmitter on the Minna. The slave stations were on Spotted Island east of Cartwright, Labrador, and on Resolution Island.
  2. Rho-rho LORAN-C, which used an Austrom 5000 LORAN-C receiver and an atomic clock to predict the instant of transmission from the LORAN-C stations at Cape Race, Newfoundland, and from Angissoq, Greenland.
  3. A Marconi Doppler satellite receiver to establish a position every few hours to verify the DECCA ‘lane count’ and to determine the clock rate (microseconds/day) of the atomic clock on the Minna versus the ones at Cape Race and Angissoq. Doppler satellite positioning needed accurate ship’s velocity during the 20 minutes of the satellite passing overhead, which was provided by DECCA and/or LORAN-C.
The geophysical survey equipment included a magnetometer, three marine gravity meters, and one land gravity meter.
Two sizes of air guns and a 100-foot (30m) towed streamer with acoustic microphones connected to receivers were used for collecting seismic reflection data.

Most of this equipment was in a purpose-built unit designed and built at Bedford Institute and lowered into #2 Hold, which became the ‘survey office’.

 MV Minna hard aground at high tide — in Resolution Island (Nunavut).
photo : John Newton

Before the Grounding

The Minna visited Godthåb (now Nuuk), Greenland, for engine repairs and to verify the marine gravimeters against land-based gravity readings.
Departing Godthåb on 16 August, she ran a line of soundings towards Saglek, Labrador, then, at 08:00 on 18 August 1974, she entered Brewer Bay near the Northeast corner of Resolution Island to pick up electronic technicians who had installed a DECCA Slave transmitter on the island and then to establish the lane count.
The wind was from the Southeast to South-Southeast at Force 4 creating a swell of 1.3m.
The Bay

The navigable portion of Brewer Bay is about 240 metres wide by 600 metres with a maximum depth of 22 fathoms (40m).
The bay is surrounded by high hills providing little shelter and it experiences heavy ground swell and a circular tidal stream when near high water.
A landing beach is located in a cove on the south shore of the bay where supplies are landed annually and temporarily stored for the radar station on Cape Warwick just north of the bay.

 CCGS Griffon maneuvering to attempt to pull MV Minna off the rock.
Image courtesy: Steve Grant

The Tide

Because Minna had a single propeller and no bow thruster, her normal turning radius was large.
The ship was riding high due to low fuel and light load and was adversely affected by the SE wind causing her to have an even larger turning radius.
Accordingly, she went outside of the surveyed area while turning.
Because of forward motion and being blown sideways, she grounded on a rock pinnacle at 09:34.
At the time of grounding, the tide was dropping but still 3.1m above datum.
A sounding by lead line on the ship’s starboard (seaward) side, just aft of where the pinnacle pierced the ship’s outer hull, found no bottom; however, the ship’s sounder showed a depth of 25 fathoms.

 CCGS Griffon tends to the wreck at low tide
photo : John Newton

The Re-floating Attempts

Having assessed the situation, the captain ordered full astern at 11:00 (height of tide now 1.8m above datum), but the stern of the ship merely turned to port, thus coming closer to being parallel to the cliff, and failed to come off the pinnacle.
To return the ship to the original heading, the captain ordered full port rudder and went forward, driving the ship farther onto the rock.
By 13:00, CCGS Griffon, a buoy tender & light icebreaker, was proceeding to Brewer Bay to provide assistance.
At 19:30 (height of tide 5.5m above datum) and again at 20:20 (height of tide now 4.8m) the Griffon tried to pull while the Minna applied full reverse, but at both times the lines parted.
On the second attempt, the broken end of the hawser fouled Minna’s propeller, thereby reducing later attempts by the Griffon acting alone.
The Griffon tried a third time at 21:15.
Only at 21:30, did the crew begin lifting some of the concrete blocks from #1 Hold.
Around 23:00, it was reported in the deck log that #2 Hold was dry but #1 Hold was flooded – an indication that the ship was becoming more damaged.

Lightening the Load

The removal of cement blocks ceased at 06:00 on 19 August owing to water rising in #1 Hold, so the hatch was covered and the booms lowered.
Three more times Griffon attempted to pull Minna off the rocks; all attempts failed.
The heavy sea and swell and the wind from the Southeast (i.e., directly from the open ocean) caused the ship to keep striking heavily on the rocks.
At 13:00, they attempted to take the hatch-cover off #2 Hold to hoist the survey equipment from the Hold, but the hinges gave out, negating that course of action – another indication that the ship was breaking apart.
The crew and the BIO staff were transferred to shore and were not particularly welcome guests at the radar site, at least until some of the ship’s provisions (especially the duty-free alcohol) were brought up from the landing beach.
Between 18 and 20 August, the BIO staff returned to the ship during periods of high tide and man-handled all the moveable equipment through the ship, up the gangways, onto the deck, and then lowered it down into the BIO barge for transfer to shore.
Nine personnel were flown to Frobisher Bay (now Iqaluit) by chartered aircraft on 20 August and to Halifax by commercial airlines the next day. CCGS Norman McLeod Rogers (buoy tender/light icebreaker) arrived to take nine of the ship’s personnel to Frobisher Bay on 21 August to get flights to Halifax.

The Retrieval of the Equipment

The scientific equipment, which had been removed from the ship, was stored in a shed near the beach. Fortunately a squadron from the Royal Canadian Navy was exiting Hudson Strait and was called upon for assistance.
HMCS Assiniboine and Saguenay [destroyers] arrived on 22 August and HMCS Preserver [supply ship] on 23 August, but the squadron commander was not going to risk his ships going into such a small bay.
Nevertheless, the Navy retrieved the off-loaded equipment by sea-boat or Sikorsky Sea King helicopters to the Preserver and ultimately returned it to Bedford Institute.
Three of the survey staff went to Newfoundland on the naval ships.
The chief scientist and nine others stayed to dismantle the DECCA Slave station and on 26 August flew to Halifax via Frobisher Bay.
On 19 September 1974, CSS Baffin [hydrographic ship] retrieved the DECCA equipment from the shore and more of the equipment from the Minna.

The End

A Norwegian ocean-going tug arrived before 5 September, but waited until the next Spring High Tide on 15 September but the tug was not successful in freeing her.
On September 19, the Karlsen Shipping Company and its insurers declared the ship abandoned as no salvage company was interested in rescuing her.

Notice to Mariners

The yearly sealift of goods to the Northern Warning System station on Cape Warwick reported in June 1998 that the wreck of the Minna had slipped into deeper water because of ice action.
A Notice to Mariners was immediately issued instructing mariners to add a dangerous wreck symbol to the 1963 Edition of CHS chart 5430 and on its inset of Brewer Bay, at 61° 34′ 56.0ʺN, 64° 38′ 23.0ʺW (local datum).
Also, a multibeam hydrographic survey with full bottom coverage positioned by GPS was carried out late that summer.
The 2005 New Edition of the chart incorporates the 1998 survey both on the main chart (for the approaches to Brewer Bay) and for the entire inset of Brewer Bay.
The main chart shows the more normal wreck symbol whereas the inset uses the wreck symbol appropriate for large-scale charts near the north shore of the bay at 61° 35′ 17.5ʺN, 64° 37′ 53.5ʺW (NAD-83) with the bow facing northwest and drying (i.e., visible) at low tide.
The present Sailing Directions, published 2009, cautions mariners that “ice action has shifted the wreck; the exact position and depth over [the wreck] are not known.”

Figure 1: The inset of Brewer Bay on CHS Chart 5340 (Approaches to Sorry Harbour) showing Minna at 61° 35′ 17.5ʺN, 64° 37′ 53.5ʺW.
Soundings are in fathoms and feet, heights above chart datum (low water) are underlined and are in feet.

The Chart

The 1963 Edition of Chart 5340 was based on a 1952-3 US Navy survey, where its geographic grid was based on an astronomically determined survey point.
The topography on the chart was from aerial photography taken about the same time.
A New Edition of the chart was required to incorporate the 1998 CHS survey and so the chart was converted to NAD-83 so that it would be compatible with GPS positioning.
The shift in the geographic grid accounts for most of the 795 metres between the two positions quoted above.
The magnitude of this shift is typical for charts that are based on exploratory quality astronomic positions.

 Figure 4: Air photo taken 18 August 1976 showing Minna lying on her starboard side, bow to the southwest, stern to the northeast.
Image courtesy: National Air Photo Library, Roll A24530, Frame 9.

Air Photos

Air photos taken in 1976 show the Minna lying on her starboard side, bow to the southwest and stern to the northeast.
In the 1987 air photos, the ship is not visible above water, but the water tones suggest that the ship is submerged at its 1976 position, although the orientation may be reversed.
In the 1993 air photos, the ship is not visible, although there may be something in the water at the 1976 position.
Google Earth, which uses a July 2006 satellite imagery, shows shallow water at the wreck’s charted location.
These series of photographs pose two questions.
  1. Was the ship moving or rotating between these various epochs?
  2. Was the ship being naturally reduced to rubble by the action of wind, waves and ice?
Perhaps the apparent movement in the air photos and the situation as found in the 1998 survey, are the reasons for the Sailing Directions’ caution note and the continuance of the ‘Position Approximate’ on the inset of the chart.

Some Thoughts

Given modern capabilities of 100% bottom coverage and remotely controlled underwater vehicles, it would be interesting to evaluate the damage done by sea-ice on the hull of the Minna after 40-plus years.

Scott and Shackleton logbooks prove Antarctic sea ice is not shrinking 100 years after expeditions


From The Telegraph by Sarah Knapton

Antarctic sea ice had barely changed from where it was 100 years ago, scientists have discovered, after poring over the logbooks of great polar explorers such as Robert Falcon Scott and Ernest Shackleton.
Experts were concerned that ice at the South Pole had declined significantly since the 1950s, which they feared was driven by man-made climate change.
But new analysis suggests that conditions are now virtually identical to when the Terra Nova and Endurance sailed to the continent in the early 1900s, indicating that declines are part of a natural cycle and not the result of global warming.

 Scott's ship the Terra Nova

It also explains why sea ice levels in the South Pole have begun to rise again in recent years, a trend which has left climate scientists scratching their heads.
"The missions of Scott and Shackleton are remembered in history as heroic failures, yet the data collected by these and other explorers could profoundly change the way we view the ebb and flow of Antarctic sea ice,” said Dr Jonathan Day, who led the study, which was published in the journal The Cryosphere.

 The Endurance, trapped in sea ice

"We know that sea ice in the Antarctic has increased slightly over the past 30 years, since satellite observations began. Scientists have been grappling to understand this trend in the context of global warming, but these new findings suggest it may not be anything new.
"If ice levels were as low a century ago as estimated in this research, then a similar increase may have occurred between then and the middle of the century, when previous studies suggest ice levels were far higher."
 Captain Scott and team

The study was based on the ice observations recorded in the logbooks from 11 voyages between 1897 and 1917, including three expeditions led by Captain Scott, two by Shackleton, as well as sea-ice records from Belgian, German and French missions.
Captain Scott died along with his team in 1912 after losing to Norwegian Roald Amundsen in the race to the South Pole, while Shackleton's ship sank after becoming trapped in ice in 1915 as he and his crew attempted the first land crossing of Antarctica.
The study is the first to calculate sea ice in the period prior to the 1930s, and suggests the levels in the early 1900s were between 3.3 and 4.3 million square miles (5.3 and 7.4 million square kilometres)
Estimates suggest Antarctic sea ice extent was significantly higher during the 1950s, before a steep decline returned it to around 3.7 million miles (6 million square kilometres) in recent decades which is just 14 per cent smaller than at the highest point of the 1900s and 12 per cent bigger than than the lowest point.

 One of the first aerial photographs of the Antarctic obtained from a balloon in 1901, showing Erich Von Drygalski's ship The Gauss

The findings demonstrate that the climate of Antarctica fluctuated significantly throughout the 20th century and  indicates that sea ice in the Antarctic is much less sensitive to the effects of climate change than that of the Arctic, which has experienced a dramatic decline during the 20th century.
In future the team plans to use data from naval and whaling ships as well as the logs from Amundsen’s expeditions to complete the picture.
Separate research by the British Antarctic Survey also showed that the present day loss of the Pine Island Glacier on the West Antarctic Ice Sheet has been happening since the mid 20th century and was probably caused by El Nino activity rather than global warming.
Pine Island Glacier, which drains into the Amundsen Sea in West Antarctica, is retreating and thinning rapidly, but the initial triggering mechanism was unclear.
The team looked a sediment cores in the area which showed that an ocean cavity under the ice shelf began to form around 1945, following a pulse of warmth associated with El Niño events in the tropical Pacific Ocean.
“We are very excited about this new finding as it provides the first direct evidence of the timing of glacier retreat even before we had satellites to measure them,” said lead author, marine geologist Dr James Smith from British Antarctic Survey.
“They show us how changes half-way across the planet in the tropical Pacific, reached through the ocean to influence the Antarctic ice sheet.”
Co-author Professor Bob Bindschadler of NASA added: “A significant implication of our findings is that once an ice sheet retreat is set in motion it can continue for decades, even if what started gets no worse.
“It is possible that the changes we see today on Pine Island Glacier were essentially set in motion in the 1940s.”
The Pine Island research was published in Nature.

Links :

Thursday, November 24, 2016

New Zealand Linz update in the GeoGarage platform

Wellington Harbour, one of the 13 nautical raster charts updated by Linz
see : News

Model upgrade brings sea-ice coupling and higher ocean resolution

The higher ocean resolution for ensemble forecasts in IFS Cycle 43r1 results in forecast fields that reveal more detailed features and fit more snugly along coastlines.
This is illustrated by these forecasts of daily mean sea-surface temperature for 18 November 2016, initialised at 00 UTC on the same day, using the previous model version (top) and the new model version (bottom).

From ECMWF

ECMWF implemented a new version of its forecasting system on 22 November, which introduces a dynamic sea-ice model and increases the resolution of the ocean model.
These and other changes to the Integrated Forecasting System (IFS) significantly improve the Centre’s weather predictions.
The interactive sea-ice model in the new IFS Cycle 43r1 is used to produce ensemble forecasts in which the atmosphere, oceans and sea-ice are dynamically coupled.
Ensemble forecasts provide a range of likely scenarios and give an indication of the degree of confidence we can have in the forecast.

Forecast of daily mean sea-surface temperature for 18 November 2016,
initialized at 00 UTC on the same day, using IFS Cycle 43r1.
 
Bringing additional Earth system components into the model and developing ECMWF's ensemble forecast capabilities are important elements of the Centre's new ten-year Strategy.
Introducing interactive sea ice also makes it possible to predict changes in sea-ice cover during the forecast. In the previous model version, sea-ice cover was left static up to forecast day 15.

Dynamic predictions of sea-ice cover produce very different results from the assumption of static sea-ice cover.
This is illustrated by this two-week ensemble forecast from 2 November 2016 (blue lines), which shows a significant evolution from the initial conditions (dashed orange line).
Subsequent verification (pink line) shows that the dynamic forecast is much closer to observations than the static sea-ice cover.
The spread of the blue lines gives an indication of the range of likely scenarios given inevitable uncertainties in the evolution of atmospheric and ocean conditions.

The sea-ice model is LIM2, the Louvain-la-Neuve Sea Ice Model developed at the Belgian Université catholique de Louvain.
It is part of the NEMO (Nucleus for European Modelling of the Ocean) modelling framework also used at ECMWF to model the ocean.
In another significant development, the resolution of the ocean model used in ensemble forecasts has gone up from 1 degree and 42 layers to 0.25 degrees and 75 layers.
This means that small-scale ocean circulation features are better captured and coastlines are better resolved than previously.

Other innovations include changes in the representation of some low-level clouds to reduce cloud cover bias, and in the coupling between the surface and the atmosphere to improve 2-metre temperature forecasts.
There are new cloud and freezing level output fields for aviation; a new sun-following radiation output for solar panels; and eight new wave model output fields, including the magnitude and direction of the wave energy flux that is responsible for the impact of waves on coastlines and offshore structures.

Better weather forecasts

Improvements in forecast skill can be seen in a range of weather parameters.
These include 2-metre temperature, in particular in ensemble forecasts, and 10-metre wind speed over the ocean.
There are also consistent gains for total cloud cover in the tropics as well as the extra-tropics.
In particular, IFS Cycle 43r1 reduces the model’s tendency to predict too much cloud at high latitudes during winter.

Improvements in cloud cover bias are particularly noticeable at high latitudes.
The plot shows the percentage change in total cloud cover bias in the new IFS cycle for 48-hour forecasts compared to observations for the period November 2015 to January 2016.
Negative values mean a reduction in bias; -100% means the bias has been completely eliminated over that period.
 
The new IFS cycle brings a range of other changes which improve the performance of specific parts of the forecasting system, including indications of severe weather.
The Extreme Forecast Index (EFI) flags up the risk of extreme weather compared to a reference climate for the relevant region and time of year.
One of the changes in IFS Cycle 43r1 is a more accurate representation of the reference climate. This leads to the elimination of spurious EFI signals in some situations.

The charts show 10-day EFI forecasts for 2-metre temperature at the northern tip of the Red Sea initialised on 8 November 2016. In IFS Cycle 43r1, the representation of the EFI reference climate has been improved.
Spurious EFI signals in the previous version (left) are thus avoided in the new version (right).

The modelling changes, together with changes in data assimilation and in the use of observations, also bring improvements to high-resolution and ensemble forecasts of upper-air parameters.
In the extra-tropics, error reductions in the order of 0.5–1% are found for most upper-air parameters and levels.
These reductions translate into improvements in ECMWF’s primary headline scores:
  • The gain in the skilful range of ensemble forecasts of 850 hPa temperature in the extra-tropical northern hemisphere (defined as the lead time at which the Continuous Ranked Probability Skill Score drops below 25%) is about 0.5 hours.
  • The gain in the skilful range of high-resolution forecasts of 500 hPa geopotential in the extra-tropical northern hemisphere (defined as the lead time at which the anomaly correlation drops below 80%) is about 1 hour.
Full details of all the changes in this model cycle are available on the web page on the implementation of IFS Cycle 43r1.